There’s an inviolable law of animated films: The more “names” you have in the voice cast, the weaker you know your film is.

Aardman, those meticulous Brits who build clay models and painstakingly animate them into “Wallace & Gromit” cartoons and the hit “Chicken Run,” tip their hand that way with “The Pirates! Band of Misfits.”

This pirate picture is too late to the party to have much in the line of fresh pirate gags. It is stuffed with voice actors, from Hugh Grant as The Pirate Captain to Salma Hayek, Imelda Stanton, Anton Yelchin and Jeremy Piven.

Amusing in small doses, “Pirates” is the first Aardman film to suffer a serious shortage of sight gags, the first where the whimsy feels forced and the strain shows.

Hugh Grant’s Pirate Captain is all Hugh Grant stutter and “glittering eyes and glorious beard.” As a pirate, he’s something of a bust, even though his crew adores him.

He figures he’s due for the “Pirate of the Year” award. But he’s always come up short in the booty and pillaging department.

And so it appears it will be in the 1837 awards, until he captures Charles Darwin (David Tennant), a scientist who craves fame as much as The Pirate Captain. And Darwin recognizes the Captain’s pet “parrot,” Polly, as something altogether more amazing. She’s the last Dodo bird.

Darwin talks The Pirate Captain into sailing to Britain, under the nose of pirate-hating Queen Victoria (Imelda Staunton), where Darwin hopes to present the bird to The Royal Society.

So you’ve got pirates roughly 120 years after their heyday, and a scheming Darwin. You’ve got other scientists, hoping to win acclaim with everything from airships to a Rubik’s Cube. You have competing pirates, all swagger and swordplay. What you don’t have is a lot of laughs.

Those of us who love Aardman will appreciate the gorgeous attention to detail. But “Pirates” plays like a fussy film made by fussy little fussbudgets, clever chaps all wrapped up with making perfect Plasticine trees but who lose track of the forest: the funny movie that is supposed to be animated around all this detail.